Telecommunications – Transmitter – Power control – power supply – or bias voltage supply
Reexamination Certificate
1999-12-13
2002-10-08
Vo, Nguyen T. (Department: 2682)
Telecommunications
Transmitter
Power control, power supply, or bias voltage supply
C455S126000
Reexamination Certificate
active
06463264
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is related to a wireless (radio) communication apparatus for performing a mobile communication in a portable telephone, related to a transmission power control method used in this wireless communication apparatus, and also related to a recording medium for recording thereon a program used to execute the transmission power control method.
In general, mobile communication appliances such as portable telephone units are equipped with functions capable of controlling transmission power of own units based upon distances between base stations and mobile stations while information is transmitted. In the multiple access type communication system for multiplexing a plurality of communication channels at the same frequency, a transmission power control for controlling power of a signal reached to a base station at a necessary minimum value is necessarily required in order to increase a frequency utilization efficiency, depending upon interference power amounts between communication channels.
More specifically, in a CDMA (Code Division Multiple Access) type mobile communication appliance with employing a spread spectrum technique, there are great possibilities that a signal having low transmission power is masked by a signal having high transmission power, namely a so-called “far
ear problem” occurs. To solve such a problem, conventionally, the transmission power control with a high linearity and a wide dynamic range (for instance, 70 to 80 dB) is required. In the wide-band CDMA (W-CDMA), higher precision of the transmission power is required when signals having high power are transmitted, and thus, higher precision of the transmission power controls is further required. This wide-band CDMA system has been considered as the mobile communication system for the next generation.
As described above, in such a case that the mobile station is located in the vicinity of the base station in the system operation of the above wireless communication apparatus, there is a certain possibility that the transmission power of both the mobile station and the base station is lowered by way of the transmission power control. At the same time, the power consumption of the transmitter can be reduced by controlling the current consumption of the power amplifier.
However, in the above-described conventional wireless communication apparatus, when the current consumption control for the power amplifier is realized by the bias current control and the like, there is a variation in the gains caused by changing the biasing point. As a result, since the high-linearity power control corresponding to the system requirement condition can be hardly carried out, generally speaking, the power amplifier is used under the fixed biasing control.
As a consequence, in order to reduce the power consumption of the transmitter while realizing the high-linearity power control, there is a limitation in the conventional wireless communication apparatus such that the current consumption of the power amplifier operated under low output is lowered. In particular, the low power consumption of the transmitter may constitute a major subject in view of extension of communication available time of a mobile station.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above-described problems of the prior art, and therefore, has an object to provide a wireless communication apparatus, a transmission power control method used in the wireless communication apparatus, and a recording medium, capable of securing absolute precision of required transmission power (i.e., allowable error with respect to power control target value), and furthermore, capable of realizing a high-linearity transmission power control with a wide dynamic range, while reducing power consumption of an electronic appliance by adjusting a current consumption of a power amplifier operated under low output power.
To achieve the above-described object, a wireless communication apparatus according to the present invention comprises: transmission power designating means for designating transmission power of a transmission signal to be transmitted from the wireless communication apparatus; controlling reference value producing means for producing a reference value used to control transmission power based upon the designated transmission power; timing control means for defining control timing of the transmission power; error detecting means for detecting an error based upon a difference value between a detection value obtained by detecting the transmission signal of the wireless communication apparatus and a detection value of a transmission signal when the transmission signal is transmitted under the designated transmission power; gain multiplying means for multiplying the detected error by a predetermined gain to obtain a correction value; control amount producing means for producing a feedback control amount based upon the correction value; power adjusting means for again setting a gain in a transmission power amplification at the control timing based upon the reference value for controlling the transmission power and the feedback control amount so as to adjust the transmission power; power amplifying means for power-amplifying the transmission signal; current consumption adjusting means for adjusting a current consumption in such a manner that a bias voltage is applied to the power amplifying means in response to the designated transmission power so as to control a bias current in the power amplifying means; and gain variation compensating means for compensating a variation in gains when the variation of the gains occurs in the transmission power amplification by controlling the bias current.
Also, in the wireless communication apparatus as above mentioned, the gain variation compensating means includes gain adjusting means for adjusting both the reference value used to control the transmission power and the gain control value based on the feedback control amount in response to the designated transmission power in the power adjusting means.
Also, the wireless communication apparatus as above mentioned, the gain variation compensating means includes compensation amount producing means for producing a gain variation compensation amount in response to the designated transmission power; and variable gain means for varying a gain based upon the gain variation compensation amount at output means of the power adjusting means.
Also, the wireless communication apparatus as above mentioned, the gain variation compensating means includes compensation amount producing means for producing a gain variation compensation amount in response to the designated transmission power; and signal amplitude varying means for varying a signal amplitude of the transmission signal based on the gain variation compensation amount.
A transmission power control method used in a wireless communication apparatus, according to the present invention comprises: a transmission power designating step for designating transmission power of a transmission signal to be transmitted from the wireless communication apparatus; a controlling reference value producing step for producing a reference value used to control transmission power based upon the designated transmission power; a timing control step for defining control timing of the transmission power; an error detecting step for detecting an error based upon a difference value between a detection value obtained by detecting the transmission signal of the wireless communication apparatus and a detection value of a transmission signal when the transmission signal is transmitted under the designated transmission power; a gain multiplying step for multiplying the detected error by a predetermined gain to obtain a correction value; a control amount producing step for producing a feedback control amount based upon the correction value; a power adjusting step for again setting a gain in a transmission power amplification at the control timing based upon the reference value for controlling the transmission
Ly Nghi H.
Matsushita Electric - Industrial Co., Ltd.
Pearne & Gordon LLP
Vo Nguyen T.
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